Metal-melting pot



393@ H. SARBROUGH 39745932@ METAL MELTING" POT Filed April 21. 1928 /a mg 2. 2

0 I l 0// I I I I /4 /3 I nventobz Harry Ecerbrou h,

WWA H is Attorney.

Patented Jan. 28, 1930 UNITED STATES PATENT OFFICE HABBY E SCARBROUGH, OF CHICAGO, ILLINOIS, ASSIGNOR 'TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK META-L-MELTING POT Application filed April 21,

This method of heat insulation, while aiding in preventing loss of heat from the surface of the molten metal, has certain disadvana tages which it is my desire to avoid. WVhen heat insulating material is used upon the molten metal, care must be taken that the upper surface level of the metal is kept app'eciably below the edge of the container so that the insulating material will not overfiow. Again, when stereotype cylinders are placed inthe bath of molten metal, ink and foreign matter adhering to the cylinders are burned off and then mix with the insulating material, causing the latter to soon become worthless. Also, when plates or cylinders for remelting are charged into the molten bath at a rapid rate, some of the insulating material often adheres to the surface of thecolder metal and prevents this metal from being readily melted.

In carrying out my invention, I provide means whereby a small portion of the surface of the molten metal will remain exposed, while the remainder of the surface is covered with heat insulating material. The plates or cylinders can be charged into themolten metal where it is exposed, and contact of the insulating material with the cold plates is thus prevented. Furthermore, ink and foreign matter will collect at 'the exposed surface of the metal and can be readily skimmed ofi' and thus a 'mixture of the insulating material with the dross will not occur.

For a more complete understanding of my 1928. Serial No. 271,856.

invention, reference may be had to the ac-- companying drawin in which Fig. 1 is a sectional elevation of an embodiment of my invention, taken on the line 1-1 of Fig. 2; Fig. 2 is a longitudinal sectional elevation on the line 2-2 of Fig. l, and Fig. 3 is a plan view. 4

Referring to the drawing, in one form of my invention, I provide a metal base plate 10 which supports at its edges a metallic wall 11. The base plate 10 and wall 11 are shown as of an oval shape but it is to be understood that the invention is not limited to a furnace of this specific shape. An up-turned edge 12 on the base plate 10 serves as a securing means for the lower edge of the wall 11. Mounted on the upper edge of the wall 11 is an oval fiange member 13 which is formed with a depending rim 14, on the outside of the wall 11, and a depending L-shaped rim 15 on the inside of the wall 11. The slot formed by these two depending rims ts over the upper edge of the wall 11 and secures the flange member 13 in place. A receptacle 16 preferably made of a refractory metal, such as cast iron, is supported by a flange 17 from the inner edge 15 of the flange member 13. The space between the receptacle 16 and the base plate 10 and wall 11 is filled with a suitable heat insulating material shown as a refractory brick-work 18.

A pair of refractory metallic frames 19 preferably made of cast iron, are supported by the fiange member 13-and fiange 17 in a horizontal position. Each frame member 19 is shown as comprising a semi-circular portion and a portion 20 connecting the ends of the semi-circular portion. The portion 20 of each frame 19 is of a height such that when the receptacle 16 is substantially full of molten metal 21, the lower edge of the members 20 will be below the upper surface of the metal 21. The semicircular portions 19 of the frames may be attached to the flange 13 by any suitable means, such as by suitable machine screws, not shown.

The metal 21 in the receptacle 16 may be heated by any suitable means and as shown a cast-in electrical immersion heater 22 is supported in the interior of the receptacle 16. The heater 22 has a suitable resistance i element embedded in refractory material and surrounded by a metal sheath. Leads 23 from the resistance element pass through an insulating tube 24 and outlet box 25 and may be connected to any suitable source of electrical supply. Inthe illustration but one heating unit 22 is shown but it is to be understood that any number of these or similar heating units may be' used. A quantityof owdered heat insulating material 26 is provded, which material floats on the upper surface of the molten metal 21 and is enclosed by the frames 19. As the level of the molten metal' rises or falls the heat insulating material will rise 'or fall correspondingly but as above stated it is to be understood that the surface level of the metal 21 should not rise above the flang'e 17 nor fall below the inner edge of the members 20. It will be observed that by enclosing the heat insulating material 26 by the frames 19,- substantially the entire upper surface of the molten metal 21 will be covered and'thus heat insulated, While a smaller ortion 27 of the molten metal surface will e exposed at all times. i By causing the cold metal, which is .to be melted, to enter the molten metal bath 21 through this exposed surface portion 27, contact of the cold metal with the heat insulating material 26 will not occur, and thus the cold metal will not be prevented from melting readily by the adherence thereto of small quantities of the heat insulating material 26. 'Furthermore`, by adding the cold metal to the bath through the exposedpore tion 27, ink and other foreign matter adhcring to the cold metal and burning off at the surface 27 may then be readily skimmed froni the molten metal surface and will be prcvented from intermixing with the heat insulating material 26.

While I have described my invention as emhodied in concrete form and Operating in a specific manner in accordanee with the pro Visions of the patent statutes, it/ should be understood that I do not ,limit myinvention thereto, since various modificatio ns thereof will suggest themselves to those skilled in the artwithout departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as new and desre to secure by' Letters Patent of the United States is:

1. In a metal melting pot, a receptacle for containing molten metal, a supporting structure for said receptacle, a pair of frames supported horizontally on said structure and over said rcceptacle arranged to hold powdered" heat insulating material resting upon the molten metal, said frames serving to prevent said insulating material from completely covering the surface of the molten metal.

2. In a type metal melting pot, the method of heat insulating the surface of the molten metal which consists in applying a quantity of vpowdered heat insulating material to the surface of the molten metal, and maintaining said insulating material over two separated portions of the surface of said molten metal to provide a charging area.

' In witness whereof, I have hereunto set my hand this '18th day of April, 1928.

. HARRY E. SCARBROUGH. 

